Poly(tetramethylene ether) glycol (PTMEG) is a commodity in the chemical industry, widely used in the manufacture of polyurethanes and polyesters. It is commonly prepared by reacting tetrahydrofuran (THF) with a strong acid catalyst and then quenching the product with water.
While this process has proved to be quite satisfactory, it is not as efficient as desired because the acid catalyst cannot be recovered and reused. Moreover, disposal of the spent acid is a problem because of its toxicity and corrosiveness.
It has now been found that PTMEG can be prepared by polymerizing THF, using
(1) A CATALYST WHICH, ALTHOUGH MORE COMPLEX THAN THAT, CAN FOR PURPOSES OF SUMMARY BE DESCRIBED AS A POLYMER CONTAINING ALPHA-FLUOROSULFONIC ACID GROUPS, AND
(2) A CHAIN TERMINATOR WHICH IS WATER OR 1,4-BUTANEDIOL.
The nature of the catalyst permits its reuse, thereby eliminating the disposal problem, and the catalyst's low solubility in the reaction mass makes it easy to separate the product from the catalyst at the end of the polymerization reaction. This low solubility also minimizes loss of catalyst as the reaction proceeds.